1. File of the Invention
This invention relates to a plate comprising a near infrared absorbing composition (hereinafter referred to as a near IR-absorbing composition) comprising both thiourea compound and at least one copper compound.
2. Prior Art
Recently, near IR-absorbing materials have been researched and developed. They have found a wide use, including light-sensitive materials using a semiconductor laser ray having a near IR-wave length range, etc. as a light source; information-recording materials such as an optical recording disk; optical materials for shielding sunlight thermic rays such as thermic ray cut plate, IR-cut filter, IR-cut film.
As hitherto developed near IR-absorbing materials, there are disclosed a chrome-cobalt complex in Japanese Patent Publication No. 60-42269, a thiolnickel complex in Japanese Laid-Open Patent Application No. 60-21294, an anthraquinone derivative in Japanese Laid-Open Patent Application No. 61-115958, a novel squarylium compound having a maximum absorption in a wave length range of 700-800 nm in Japanese Laid-Open Patent Application No. 61-218551.
Further, there are described a nitroso compound, metal complex thereof, a polymethine dye (cyanine dye), a cobalt-, platinum-, or palladium-complex of thiol, Phthalocyanine dye, triarylmethane dye, immonium dye, diimmonium dye, a naphthoquinone dye, and the like in "Near IR-absorbing dyestuff" (Kagakukogyo, 43, May 1986).
Among the conventional near IR-absorbing materials, the organic materials have the defects that the durability is inferior and the original abilities deteriorate with the change of condition or the lapse of time, particularly the weather resistance is insufficient for the exterior plates. On the contrary, the complex-base materials, which exhibit a good durability, have defects that they are strongly colored owing to the absorption of both visible range and near infrared range, and they have not sufficient transmittance in the visible range whereby their uses are limited. Both materials indicate an absorption peak at a particular wave length and have little absorbency in the range of outside the particular wave length. For an efficient cut of thermic rays from the sunlight rays, it is required that several absorbers are used. It is said that this combination hardly exists taking the absorbency, durability, coloring, costs, etc. into consideration. This use is extremely limited.